What I find very unusual is that you are getting an 89 fps gain for a 0.5 gr powder increase (43.5 to 44.0 gr) and 186 fps gr with a 1.0 gr increase (43.5 to 44.5). I've never seen that with ANY powder in a .308 do that and it is not in line with Hornady data for that powder. Typical for a .308 is 50 - 60 fps per grain. You're seeing a 3x higher increase per grain - I don't think that's good and have no explanation for it.
Seen where Accurate over the years has claimed as much as 300 fps gain in 1.3 grains addition of powder. Same caliber, bullet and barrel length actual measured was 263. They changed the data later on making it ~ 2.5 grains for 290 fps gain. Actually it was a little bit more for me 338 fps for 2.5 grains. Go figure
